Each year thousands of dogs die in hot cars, a tragedy that's easily preventable. When I travel to agility trials, sometimes I leave my crew in our SUV while I make a quick rest stop. I know not to do this in warm weather, but I didn't know until recently how fast cars can heat up even in more mild temperatures. On a 75 degree day, vehicles can heat up to 100 degrees in just 10 minutes. Scary stuff.